1. Field of the Invention
The present invention relates to a method for manufacturing an organic electroluminescent (EL) display device using organic electroluminescence elements (the organic EL elements), particularly to make a pattern of emitting portions in the organic EL display device.
2. Description of the Related Art
In conventional emitting elements, there is an electric field emitting element such as an organic electroluminescence (EL) emitting element which has an emitting surface having various patterns such as letters, designs or the like, or a plurality of pixels or the like emitting the same.
FIG. 2 is a schematic cross sectional view of a conventional organic EL display device having organic EL emitting elements. In this figure, the organic EL display device is constructed in such a manner that transparent anodes 102 are formed in turn on a transparent glass substrate 101, and then emitting layers 103 each including organic fluorescent substance layers and an organic hole transport layer or the like are formed in turn with a pattern such as predetermined letters, designs or the like on the transparent anodes 102 by using the pattern-masking and vacuum-depositing method or the like, and then cathodes 104 made of metal are formed with the pattern on the emitting layers 103 by using the pattern-masking and vacuum-depositing method or the like.
In addition, a protective layer 105 is formed on the cathode 104 to prevent the deterioration of the emitting layer 103 and the oxidation of the cathode 104.
In such an organic EL display device, the emitting layer 103 disposed between the cathode 104 and the anode 102 emits light when applied a predetermined voltage across these electrodes by a power supply 106, so that the pattern such as predetermined letters, designs or the like of the emitting layer 103 is displayed through the transparent glass substrate 101.
In recent years, there is in demand for the display apparatus using the organic EL element to be minimized in its pixels and precise shapes of emitting portions thereof in accordance with varieties of information and a high density on the recording medium. Therefore, it is necessary to process the patterns of the emitting layer and the cathode at a high precision in the flexible display panel manufacture.
On the other hand, the pattern-masking and vacuum-depositing method above mentioned is restricted in accuracy of the alignment for the fine mask pattern with the substrate. It is therefore difficult to manufacture, at a high accuracy, the display panel having a plurality of organic EL elements each having a minute pattern.